Analysis of free energy functional density expansion theories

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Density expansion theories are often used, within the density functional formalism, to approximate the Helmholtz free-energy functional of simple classical fluids. An overview of the theoretical framework of density expansion theories is presented. Several density functional theories that employ truncated density expansions are then analysed with attention focused on their thermodynamic properties. It is found that, of these theories, only the commonly used mean-field theory satisfies the Gibbs adsorption equation; the inconsistencies within the other theories arise from truncation of the density expansion without appropriate modification of the expansion coefficients. Other repercussions of truncating the density expansion are discussed.
Original languageUndefined/Unknown
Pages (from-to)573-581
Number of pages9
JournalMolecular Physics
Issue number9
Publication statusPublished - May 2000


  • Physics
  • Engineering (General). Civil engineering (General)
  • kinetic theory
  • quantum mechanics
  • group theory
  • mathematical physics
  • nuclear physics
  • physical chemistry
  • thermodynamics theory
  • chemical physics
  • atomic physics
  • theoretical physics

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